The field of the present invention is cartridges for ribbons used in printing, including cartridges to be mounted in stacked relation with other cartridges in a printing device.
Ribbon and tape cartridges for use in printing devices such as typewriters and the like are known. Cartridges containing ribbon are typically used to transfer information from the printing device to a tangible medium such as a sheet of paper. Cartridges containing tape are typically used for making corrections to previously printed matter.
In some printing apparatus, an ink ribbon cartridge and correction tape cartridge are simultaneously mounted in stacked relation in the printing device such that printing and correction can be performed without exchanging cartridges. In some cases, the printing apparatus includes a power activation switch that is activated by a tab extending from an overlying ink ribbon cartridge when the ink ribbon cartridge is properly positioned in the printing device. Because the correction tape cartridge is positioned between the ink ribbon cartridge and the printer, it is provided with a corresponding slot to receive the tab extending from the ink ribbon cartridge and permit the tab to extend to the power activation switch. An arrangement of this type is shown in U.S. Pat. No. 4,900,171, the contents of which are incorporated in full herein by this reference.
In the arrangement of U.S. Pat. No. 4,900,171, a first ink ribbon cartridge includes a single tab that is fixedly positioned in a first position in alignment with an associated slot in a first underlying correction tape cartridge and in alignment with a first underlying power activation switch. In a second ink ribbon cartridge, a tab is fixedly positioned in an alternate second position spaced from the first tab position so as to align with an associated slot in a second underlying correction tape cartridge and an associated second power activation switch. With such an arrangement, the resultant combination of ink ribbon and correction tape cartridges which may be used together in a printing device are limited to those which have mutually aligned tabs and slots. A ribbon cartridge having a tab which does not align with the slot in the underlying correction cartridge cannot operate the power activation switch and the printer cannot be used.
In order to enhance the field of use of ink ribbon cartridges having a fixed tab, in order that such cartridges can be used with a greater number of correction tape cartridges, some manufacturers have provided correction cartridges having a pair of slots that are adapted to receive tabs located in either of the aforementioned first and second tab positions and thus enable the tabs to engage an associated underlying power activation switch. Other manufacturers have proposed tape cartridges having a single elongated slot spanning both the first and second tab positions. Still other manufacturers have proposed tape cartridges having no central surface area to block the ribbon cartridge tabs and such cartridges therefore have no slots. Correction tape cartridges of this type do not physically lock out ribbon cartridges with incompatible tabs, and can be freely used with either of the aforementioned first and second ribbon cartridges. A "non-lockout" system is thus provided that does not assure or require cartridge compatibility.
Notwithstanding the foregoing use of two-slot, elongated-slot and no-slot correction tape cartridges, users who wish to purchase single slot correction tape cassettes are still restricted as to the type of overlying ink ribbon cassette which may be employed, and such consumers are forced to purchase only those ribbon cartridges having compatibly positioned fixed tabs. Accordingly, there is an evident need for an ink ribbon cassette that is operable with a plurality of tape cartridges including single-slot, double-slot, elongated-slot and no-slot cartridge configurations. Such a ribbon cartridge would not be physically prevented from operating with tape cartridges designed to lock out certain ribbon cartridges.